Process for use in etching the outer surface of a metal member

Abstract

A process and an apparatus within which there is provided at least one, or a plurality of tanks in series relation, depending upon the type of member being treated, each tank having one or more openings within its walls, respectively, which are provided in alignment with each other. With this apparatus, one or more metal members such as for example, a bar, rod, pipe, or tube, is rotatably fed through the aforenoted openings into the tank or tanks, thereby enabling a continuous automatic-etching process of the outer surface of the metal members to be performed. As an alternative, there is provided within each tank, a triple walled cylindrical body or solution flow guide, whereby a solution for etching may uniformly flow in the direction of the metal member being conducted through the tank or tanks, and along the outer surface thereof, so that a desired surface condition of the bar, rod, pipe or tube may be obtained in an efficient manner.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 
     
       1. An etching process for use in chemically etching the outer surface of a metal member in a plurality of tanks including inlet and outlet openings in the front and rear opposed walls thereof, comprising the steps of: positioning said plurality of tanks in series and aligning said inlet and outlet openings of said tanks, respectively;   disposing an etching treating solution within each of said plurality of tanks;   feeding said metal member though said inlet and outlet openings of said tanks and through said tanks in a direction parallel to the longitudinal axis of said member while rotating the same about said longitudinal axis thereof;   immersing said metal member in said etching treating solution within each of said plurality of tanks;   forceably conducting etching treating solution in the axial direction of feeding of said metal member within each of said tanks; and   independently feeding said metal member through said inlet and outlet openings and through said tanks in a continuous and sequential manner while rotating said metal member.   
     
     
       2. An etching process for use in chemically etching the outer surface of a metal member in a plurality of tanks including inlet and outlet openings in the front and rear opposed walls thereof, comprising the steps of: positioning said plurality of tanks in series and aligning said inlet and outlet openings of said tanks, respectively;   disposing an etching treating solution within each of said plurality of tanks;   feeding said metal member through said inlet and outlet openings of said tanks and through said tanks in a direction parallel to the longitudinal axis of said member while rotating the same about said longitudinal axis thereof;   forceably conducting etching treating solution in a travelling direction opposite that of said metal member being fed within said tanks; and   feeding said metal member through said inlet and outlet openings and through said tanks in a continuous and sequential manner while rotating said metal member.   
     
     
       3. An etching process as set forth in claim 1, wherein said step of disposing an etching treating solution within each of said plurality of tanks includes; disposing a first acid in a first tank; and   disposing a second acid relatively more concentrated than the first acid in a second tank so as to provide varying degrees of etching to the outer surface of said metal member.   
     
     
       4. An etching process as defined within claim 1, wherein said process further comprises the steps of: water-rinsing said metal member, so as to remove said etching treating solution which may adhere to the surface of said metal member, between adjoining tanks.   
     
     
       5. An etching process as defined within claim 1, which further comprises: maintaining the levels of said etching treating solutions in said plurality of tanks in such a manner that said etching treating solutions cover the entire length of said metal member.   
     
     
       6. An etching process as defined within claim 1, wherein: receiving and returning etching treating solution overflowing through the interstices defined between the wall of said tank defining said inlet and outlet openings and said metal member to a corresponding one of said tanks.